Three-dimensional stereology as a tool for evaluating bladder outlet obstruction : a pilot study

Objective. In a pilot study we evaluated whether implementation of a novel 3D stereologic technique can prove that bladder outlet obstruction (BOO) is associated with morphologic changes in the bladder wall. Material and methods. Ten males (mean age 69.7 years; range 58–84 years) with lower urinary tract symptoms (LUTS) suggestive of BOO and five controls (mean age 48.6 years; range 43–53 years) without LUTS were studied. All participants underwent a full examination, including determination of the International Prostate Symptom Score, laboratory analysis and a urodynamic evaluation. A cold-cup biopsy, taken during cystoscopy, was stereologically evaluated to determine the smooth muscle cell volume and the fractions of collagen and smooth muscle using light and electron microscopy. Results. The collagen fraction was higher in patients than in controls (probably because the patients were older). There was no relation between the Abrams–Griffiths number and either the interstitial fraction or the collagen fraction. Furthermore, the results suggest an age-associated effect of morphological changes in the bladder wall. The smooth muscle volume also showed no relationship with the severity of obstruction. Conclusions. This pilot study shows that, even with the implementation of subtle morphometric techniques, there seems to be no relationship between the severity of BOO and bladder wall morphology. It is possible that interstitial collagen in the bladder wall increases with age. It seems that bladder wall morphology is heterogeneous within small areas.